public class test {
    public static void main(String[] args){
        String arr="abvlkasjdl";
        System.out.println(arr.length());
        int a = 10;
        int b = 2;
        System.out.println();//+就是拼接的意思
        System.out.println("a + b = "+a+b); //非
        System.out.println("a + b = "+(a+b));//最后运算到啥 整体就是输出啥 任何类型跟string运算结果都是string
        int aa = 130;
        float bb = 3.5f;
    }
}
